This invention relates to outrigger mechanisms for raising or lowering a trailer or other wheeled vehicle between a position supported by the vehicle wheels and a position supported by the outrigger mechanisms. U.S. Pat. No. 3,912,288 issued Oct. 14, 1975 shows an outrigger-vehicle assembly suited for use of the invention.
In FIG. 2 of the referenced patent there is shown an outrigger 16 adapted to be moved between a stored position (indicated by dashed lines) and an operating position (full lines). The power mechanism for operating the outrigger comprises a motor 36 and ball screw 38. In practice the motor-ball screw unit has proven to be a relatively expensive piece of apparatus.
The exact reasons for the high purchase price of the motor-ball screw are not entirely known. It is believed that one cost element is the need for precise tolerances on the ball screw surfaces; also, the ball and screw surfaces are required to be hardened. The balls and screw are subjected to high loads and speeds. Precision manufacture is apparently necessary to prevent localized high load unit forces and resultant premature wear.
The present invention is directed to a relatively low cost power mechanism for operating a vehicle outrigger between its stored position and its operating position. In its preferred form the power mechanism comprises a motor-operated winding drum having a cable wound thereon; the free ends of the cable connect with anchorages at spaced points on a leg structure that forms part of the outrigger. The cable is oriented so that rotation of the drum in one direction causes the cable to pull the outrigger to its operating position; drum rotation in the opposite direction causes the cable to pull the outrigger to its stored position.
The invention has for its principal object the attainment of outrigger power mechanism that is manufacturable at relatively low cost. The mechanism can be built to relatively loose (coarse) tolerances; no precision fits or surfaces are required.